The present invention relates generally to the field of liquid containers, and more specifically, is directed to a squeezable type dispenser for dispensing fluid, such as liquids and low viscosity material.
The prior art recognizes the need for a squeezable type container for such household products as hair shampoo, liquid soaps and certain foods. One such container is described in U.S. Pat. No. 4,314,658 issued in the name of Laauwe and U.S. Pat. No. 4,324,349 issued in the name of Kaufman.
The Laauwe patent discloses a squeezable bottle which has a mouth provided with a dispensing valve. The valve is elastically biased in a normally closed position and is forced open by the pressure of the product as the bottle is being squeezed and partially collapsed. After the required amount of product has been dispensed, the bottle is returned to its uncollapsed condition by allowing air to be vented back into the bottle through one or more permanently open passageways formed in the valve. The passageways are sufficiently small so that air can pass through but not the relatively viscous product being dispensed from the bottle.
The Kaufman patent also discloses a squeezable bottle type dispenser. In the Kaufman dispenser, the liquid to be dispensed is forced through an air pocket and down an outlet passageway as the bottle is squeezed. When the bottle is released, air is drawn back through the outlet passageway in order to restore the air pocket and to clear any residual liquid from the outlet passageway.
While the above prior art squeezable bottles represent an improvement over prior designs, they remain deficient in a number of areas. For example, the Laauwe bottle is not practical for a totally inverted product container position and requires a great deal of experimentation in order to determine the correct cross-sectional area of the air passageway for venting air into the bottle while at the same time keeping product form escaping through the passageway. Moreover, such a bottle has limited utility as the passageway must be designed for each specific product having a different viscosity. The Kaufman bottle requires a mounting support in order to hold the bottle in an inverted position during the dispensing operation. Thus, the Kaufman approach is cumbersome and also expensive.